Which of the following describes the reliability of written questions?

The reliability of written questions refers to their ability to produce consistent results when administered multiple times. This means that if a student answers the same set of questions at different times, the results should reflect a similar level of understanding or knowledge, assuming that their knowledge hasn't changed. The consistency of responses indicates that the written questions effectively measure the student's comprehension of the subject matter, irrespective of external factors or fluctuations in mood.

Other options address different aspects that do not pertain directly to reliability. For instance, dependence on student mood suggests variability that contradicts the idea of reliability. The ability to change questions at any time refers to flexibility in assessment rather than their reliability. Lastly, suggesting that questions should be subjective to interpretation implies ambiguity, which could lead to inconsistent results rather than reliability. Therefore, the characteristic that written questions yield consistent results in multiple attempts is the cornerstone of their reliability.